Mosquito net fishing endangering humans and wildlife, new study

By:
Clare Fischer
Date posted:
31 January 2018

The first-ever global assessment to gauge the international scale of the practice of mosquito net fishing (MNF) has revealed a method that is of increasing concern to the global conservation and healthcare communities alike.

Madagascar, as an example, appears to have people fishing with these nets along much of its coastline and inland waters.

Rajna Gurung,
MCS Seafood Sustainability Advocate

Rajina Guring, MCS Seafood Sustainability Advocate, who co-authored the report whilst at Imperial College London, said the study is of great use because it is the first global perspective of the prevalence and characteristics of mosquito net fishing and highlights why collaborative solutions must be identified.

The report, published in the journal PLOS ONE, raises questions regarding the threats to biodiversity this practice poses, as well as its impact on both the fish populations that represent critical sources of food for many poor people, and human health.

The researchers surveyed expert witnesses living and working in malarial zones around the world, to produce a rapid global assessment of the extent and characteristics of MNF. The study found evidence that this practice occurs to some extent across most of the world’s tropical latitudes, impacting a broad range of different marine and freshwater habitats and species.

Rajina Gurung led on the collection of eyewitness accounts, and said: “We tried to get our survey out to as many people in the international healthcare, conservation and fisheries communities as possible, and the response was geographically very broad. Madagascar, as an example, appears to have people fishing with these nets along much of its coastline and inland waters.”

Dr Jean-Luc Solandt, Principal Specialist at MCS, observed MNF first hand in Tanzania: “I saw MNF in Mtwara, Tanzania in a wonderful 12km square bay enriched by old-growth mangrove forests. There were huge numbers of juvenile fish that were regularly scooped out of the bay by (mainly) women fisherfolk within the intertidal. I was amazed at the amount of juvenile reef fish that were caught and concerned about the potential impact of such fishing on the fish stocks in the reef”

Commenting on the study, lead author Rebecca Short from ZSL’s Institute of Zoology said: “Recent decades have seen the broad distribution of free or subsidised mosquito nets, which has had a hugely important impact on reducing incidences of malaria in developing countries. While anecdotal evidence has long existed about these mosquito nets often being diverted into artisanal fishing, our study represents the first concerted attempt to gauge the scale and extent of this problem worldwide.

“We are wholly supportive of the efforts of the healthcare community to tackle this disease, which is so damaging to many people’s lives, but there needs to be further research into the potential impacts of this unintended consequence.”

Particularly prevalent in Sub-Saharan Africa, MNF is conducted at a range of scales, using a variety of different fishing methods that often result in the capture of juvenile fish. This may undermine fisheries’ management efforts, potentially threatening these fish stocks and the human populations that rely on them for their survival. However, the study also points to this activity often being conducted by vulnerable fishers, providing a valuable source of food for poor families and calling into question whether simply criminalising MNF is an appropriate response.

As well as attempting to measure the true scale of the issue, the study makes a number of recommendations for policy priorities designed to mitigate against, and address the drivers of, MNF in the future. These include better planning for mosquito net distribution efforts and for their disposal after use, as part of efforts to protect marine and freshwater biodiversity whilst conserving vital fish stocks.

Co-author Professor EJ Milner-Gulland from the Interdisciplinary Centre for Conservation Science, University of Oxford added: “We hope that this study will encourage closer cooperation between healthcare, international aid/development bodies and conservationists to develop collaborative solutions to a complex issue that is linked to wider issues of poverty and food shortages in these malaria-afflicted regions.”